Does it matter?

<p>one of my teacher recs i mailed and sent, but there was no writing on the face of the letter. it was blank, and on the back she just signed her name on the flap as to officially mark it. some of my college's application status pages are saying that they dont have this teacher rec...should i have marked the front of this letter? or does it not matter? the documents on the inside have my name and her name regardless...</p>